Fig 2. Evaluation on the symmetry of accuracy measures to over-estimates and under-estimates.

A: Synthetic time series data where Y_t is the target series and $F_t^n$ are forecasts. $F_t^1$ makes a 10% over-estimate to all observations of Y_t, while $F_t^2$ makes a 10% under-estimate. B: Results of symmetric evaluation, which shows UMBRAE and all other accuracy measures except sMAPE are symmetric.